A process cartridge in the prior art is detachably installed in an electrophotographic image forming device. Said electrophotographic image forming device is internally provided with a rotational force driving head. Said process cartridge comprises a photosensitive member for bearing an image carrier and a photosensitive member hub provided at one end of said photosensitive member, inclined teeth are arranged on the outer circumference of said photosensitive member hub, the interior of the photosensitive member hub is provided with a cavity, and meanwhile a rotational driving force receiver which is capable of being engaged with a rotational force driving head inside said electrophotographic image forming device and is used for transmitting rotational force to said photosensitive member is arranged on the photosensitive member hub.
FIG. 1 to FIG. 2 illustrates the engaging process of the rotational force driving head and the rotational driving force receiving head in the prior art. As shown in FIG. 1a, 11 is the rotational force driving head in the electrophotographic image forming device, and transmission pins 111 for transmitting force are arranged on the rotational force driving head; 201 is a photosensitive member arranged in the process cartridge, 202 is a photosensitive member hub provided at one end of said photosensitive member, and 203 is the rotational driving force receiving head arranged on said photosensitive member hub; a force transmission part 2032 capable of being engaged with said photosensitive member hub to transmit force and a force receiving part 2031 capable of being engaged with the transmission pins 111 on said rotational force driving head 11 to transmit the force are arranged on said rotational driving force receiving head. During the process that the process cartridge is installed in the electrophotographic image forming device, the rotational driving force receiving head needs to be inclined (as shown in FIG. 1a) relative to the axis L1 of said photosensitive member in advance. As shown in FIG. 1a, during the installation process of the process cartridge, the looseness of internal parts of the electrophotographic image forming device is caused by assembly error; during the installation process of the process cartridge, the part, close to the rotational force driving head, of the rotational driving force receiving head 203 may interfere with said rotational force driving head, while along with continuous installation of the process cartridge, the rotational force driving head 11 promotes the rotational driving force receiving head to be straightened, but if the rotational force receiving head 11 is incapable of being engaged with the rotational driving force receiving head 203 normally, the process cartridge cannot be installed in place, the condition as shown in FIG. 1b may appear, and thus normal engagement between the rotational driving head 11 and the rotational driving force receiving head 203 as shown in FIG. 2 cannot be realized.